NIST Hydrocarbon C7H8 tables

C₇H₈ - 1,3,5-Cycloheptatriene

Molecular constants for 1,3,5-Cycloheptatriene
Parameter	Value	Ref.
A″ [MHz]	3697.1399(3186)	^a
B″ [MHz]	3671.0757(3135)
C″ [MHz]	2032.3077(44)
τ₁ [kHz]	-28.727(6485)
τ₂ [kHz]	-6.3714(14052)
τ₃ [kHz]	9.92(230) ^b
τ_aaaa [kHz]	0 ^c
τ_bbbb [kHz]	12.59(447)
τ_cccc [kHz]	-0.645(200)
Electric Dipole Moment
µ_a [C · m] µ_a [D]	0.80(13) x 10^-30 0.24(4)	65033
µ_c [C · m] µ_c [D]	0.200(7) x 10^-30 0.060(2)	65033

^a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).

^b Value fixed by setting R₆ = 0.
^c Fixed at zero.

C₇H₈ - Toluene

Molecular constants for toluene
Species	A [MHz]	B [MHz]	C [MHz]	Ref.
Normal	5729.325(217)	2517.447(9)	1748.872(20)	67034
Me - ¹³C	5729.49(15)	2444.590(10)	1713.364(10)	73085
1 - ¹³C	5730.215(141)	2506.420(6)	1743.528(6)	81048
2 - ¹³C	5638.549(277)	2516.859(16)	1739.904(15)
3 - ¹³C	5638.572(100)	2500.599(4)	1732.217(43)
4 - ¹³C	5729.63(12)	2474.926(5)	1728.233(5)
2 - d₁	5448.87(10)	2509.758(10)	1718.212(10)	73085
3 - d₁	5453.73(20)	2480.551(10)	1704.917(10)
4 - d₁	5729.56(15)	2413.638(10)	1698.125(10)
Me - d₃	5728.92(20)	2235.981(10)	1608.126(10)
Electric Dipole Moment
µ_a [C · m] µ_a [D]	1.251(33) x 10^-30 0.375(10)			67034
Internal Rotation Constants
V₆	4.879(35) cm^-1			67034
I_α	3.14 u Å² cm^-1			67034

C₇H₈ - Spiro[2.4]hepta-4,6-diene

Molecular constants for the ground state of spiro[2.4]hepta-4,6-diene
Parameter	Value	Ref.
A″ [MHz]	6102.1458(157)	^a
B″ [MHz]	2454.224 68(128)
C″ [MHz]	2028.89179(132)
τ₁ [kHz]	-6.3183(1441)
τ₂ [kHz]	-1.6455(451)
τ₃ [kHz]	1.5(14) ^b
τ_aaaa [kHz]	0 ^c
τ_bbbb [kHz]	-0.76152(4128)
τ_cccc [kHz]	-0.3815(419)
Electric Dipole Moment
µ_a [C · m] µ_a [D]	3.159(10) x 10^-30 0.947(3)	80035

^a J. Phys. Chem. Ref. Data 18(3), 1245-1524 (1989).

^b Value fixed by setting R₆ = 0.

^c Fixed at zero.

Molecular constants for some isotopically substituted species of spiro[2.4]hepta-4,6-diene
Species	A [MHz]	B [MHz]	C [MHz]	Ref.
1 - ¹³C	6052.345(114)	2410.269(5)	2003.061(3)	81040
3 - ¹³C	6102.025(205)	2451.877(8)	2027.310(5)
4 - ¹³C	6003.000(94)	2452.051(5)	2016.335(3)
5 - ¹³C	6063.945(136)	2419.796(8)	2001.166(4)
1 - d₁	5934.441(19)	2387.133(1)	1988.101(1)
4 - d₁	5766.973(71)	2454.162(2)	1990.343(3)
5 - d₁	5977.960(57)	2375.489(2)	1961.592(2)

NIST Physical Measurement Laboratory